SpringCloud 启动Nacos报错

先看一下完整错误：

java.lang.IllegalStateException: failed to req API:/nacos/v1/ns/instance after all servers([127.0.0.1:8848]) tried: failed to req API:127.0.0.1:8848/nacos/v1/ns/instance. code:503 msg: server is DOWN now, please try again later!
at com.alibaba.nacos.client.naming.net.NamingProxy.reqAPI(NamingProxy.java:467)
at com.alibaba.nacos.client.naming.net.NamingProxy.reqAPI(NamingProxy.java:389)
at com.alibaba.nacos.client.naming.net.NamingProxy.registerService(NamingProxy.java:191)
at com.alibaba.nacos.client.naming.NacosNamingService.registerInstance(NacosNamingService.java:207)
at com.alibaba.cloud.nacos.registry.NacosServiceRegistry.register(NacosServiceRegistry.java:64)
at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.register(AbstractAutoServiceRegistration.java:239)
at com.alibaba.cloud.nacos.registry.NacosAutoServiceRegistration.register(NacosAutoServiceRegistration.java:76)
at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.start(AbstractAutoServiceRegistration.java:138)
at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.bind(AbstractAutoServiceRegistration.java:101)
at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.onApplicationEvent(AbstractAutoServiceRegistration.java:88)
at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.onApplicationEvent(AbstractAutoServiceRegistration.java:47)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:165)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:554)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
at com.sinosoft.access.AccessApp.main(AccessApp.java:25)

本来好好的，突然就保这个错误，不知道为啥一顿百度，最后将nacos/data文件夹中的protocol删掉就可以了。不知道什么原因，就感觉很SB。有知道的大神，欢迎分享。